Alonzo jackson



(No Model.)

A. JACKSON.

BALANCED SLIDE VALVE.

NO. 312,858. 7 Patented Febr24, 1885.

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BALANCED SLIDE VALVE.

SPECIFICATION forming part of Letters Patent; No. 312,858, dated February 24, 1885.

Application filed October 2, 1884.

To col-Z whom it may concern:

Be it known that I, ALONZO JACKSON, a citizen of the United States, residing at New York, in the county and State of New York, have invented new and useful Improvements in Balanced Slide-Valves, of which the following is a specification.

This invention relates to improvements in balanced s1ide-valves; and it consists in the novel construction and combination of de vices hereinafter described and claimed, reference being had to the accompanying drawings, illustrating my invention, in wl1ich Figure 1 represents a longitudinal section of a steam-cylinder provided with my balance-valve. Fig. 2 is a face View of the cover of the valvechest detached.

Similar letters indicate corresponding parts.

In the drawings, the letter A designates the cylinder of a steam-engine. B is the "alvechest, and O is the slide-valve. The slidevalve is seated on the bottom of the valvechest, and steam is admitted to it through a pipe, D, which enters at any suitable point. E is the exhaust-port, and F F are the steamports.

With the slidevalve O is combined a counterbalance-plate, G, which has its seat on the cover H of the valve-chest. Said count-erbalance-plate is connected to the slidevalve by one or more columns, a, which are provided with top and bottom flanges, b o, and secured to the slide-valve by screws (1, and to the counterbalanceplate by screws 0. Said columns extend through a slot,f, in the cover of the valve-chest, so that they do not interfere with the movement of the slide-valve. By referring to Fig. 1 it will be seen that the inner surface of the coimterbalance-plate is exposed to the action of the live steam,which also acts upon the back of the slide-valve, and if the area of the exposed inner surface of the counterbalance-plate is equal to the area of the back of the slide-valve the latter is balanced against the action of the live steam. At the same time the outer surface 'of the counterbalance-plate is exposed to the pressure of the atmosphere, and the inner surface of the slide-valve is exposed to the pressure of the exhaust-steam, so that the action of the exhaust-steam on the slide-valve is counterbalanced by the action of the atmosphere 011 the counterbalance-plate, or nearly so. Of course the area of the counterbalance-plate must be changed according to the (No model.)

] nature of the engine. If my slide-valve is used for a low-pressure engine, the area of the exposed inner surface of the counterbalanceplate must be somewhat larger in proport on to the exposed area of the slide-Valve than it is if the slide-valve is used for a high-pressure engine; but it will be readily seen from the foregoing description that by properly gaging the area of the counterbalance-plate G the slidevalve can be balanced in regard to the pressure of the live steam, as well as in regard to the action of the exhaust. The counterbalance-plate is made detachable from the slidevalve, so that either the valve or plate can be ground down upon its seat independent of each other.

. In order to be able to seat Valve and plate correct/1 y, I provide the cover H with a recess, into which is placed a sheet, 9, of india-rubber, and also a metallic plate, h, which latter forms the seat for the counterbalance-plate. The plate It is secured to the cover H by screws 2', and by means of these screws and the elastic support gthe plate It can be so adjusted that both the slide-valve and the counterbalance-plate are correctly seated.

I do not broadly claim a slide-valve connected with a counterbalance-plate seated on a valve-chest and exposed to the pressure of steam or of the atmosphere; but

\Vhat I claim as new, and desire to secure by Letters Patent, is

1. The combination, with the slide-valve O and the exhaust-port E, situated beneath said slidevalve,and with the counterbalance-plate, which is firmly connected to the slide-valve, of a yielding seat for said counterbalanceplate arranged on the outside of the valveohest, substantially as and for the purpose described. 1 V

2. The combination.substantially as hereinbefore described, with the slide-valve, and with the counterbalanceplate firmly connected to the slide-valve, of the metallic plate h, secured to the valve chest and forming the seat for the counterbalance-plate, and of the elastic support placed beneath said metallic plate.

In testimony whereof I have hereunto set my hand and seal in the presence of two subscribing witnesses.

ALONZO JACKSON. [L. s] Witnesses:

W. HAUFF,

E. F. KASTENHUBER. 

